Effect of chloride solutions on portland cement

Abstract

Abstract Expansion of hardened normal Portland cement in chloride solutions exceeded that in distilled water, but specimens made of ground cement‐clinker were not appreciably affected by the presence of chloride ions. Addition of chloride ions to sulphate solutions caused increased expansion of cement pastes, but the combined effect of chloride and sulphate ions was less than that of the sum of the separate components. Magnesium and calcium chloride were more aggressive than sodium and potassium chloride. In chloride solutions, richer cement pastes were more strongly expanded than poorer ones, in contrast to their behaviour in sulphate solutions. The results are interpreted in terms of the rates of formation of calcium chloroaluminate, the effect of chloride ion on sulphoaluminate crystallisation, slight variations in composition of the chloride phase and leaching of some of the reaction products.